Flexible display panel, fabrication method, and flexible display apparatus

ABSTRACT

A flexible display panel and a flexible display apparatus are provided. The flexible display panel comprises a flexible substrate, an organic light-emitting layer disposed on a side of the flexible substrate and having a first side facing the flexible substrate and an opposing side, and a thin-film-encapsulation layer disposed on the opposing side of the organic light-emitting layer and including at least one organic encapsulation layer and at least one inorganic encapsulation layer. The flexible display panel includes at least one bending area. The at least one organic encapsulation layer has a first side facing the flexible substrate and an opposing side. In the at least one bending area, at least one groove is formed on the opposing side of the at least one organic encapsulation layer. A bottom width W of the at least one groove is configured to be 
     
       
         
           
             W 
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               π 
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                 R 
                 .

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims the priority of Chinese Patent Application No.CN201611238279.2, filed on Dec. 28, 2016, the entire contents of whichare incorporated herein by reference.

FIELD OF THE DISCLOSURE

The present disclosure generally relates to the display technology and,more particularly, relates to a flexible display panel, a fabricationmethod for the flexible display panel, and a flexible display apparatus.

BACKGROUND

Emerging flexible display technology has gained a lot of attention. Whenbending an existing flexible display panel, due to the thickness of theflexible display panel, a substantially large bending stress isgenerated in the flexible display panel. The substantially large bendingstress easily causes cracks or even breakage in the bending area of thedisplay panel.

The disclosed flexible display panel, fabrication method for theflexible display panel, and flexible display apparatus are directed tosolve one or more problems set forth above and other problems.

BRIEF SUMMARY OF THE DISCLOSURE

One aspect of the present disclosure provides a flexible display panel.The flexible display panel comprises a flexible substrate, an organiclight-emitting layer disposed on a side of the flexible substrate andhaving a first side facing the flexible substrate and an opposing side,and a thin-film-encapsulation layer disposed on the opposing side of theorganic light-emitting layer and including at least one organicencapsulation layer and at least one inorganic encapsulation layer. Theflexible display panel includes at least one bending area. The at leastone organic encapsulation layer has a first side facing the flexiblesubstrate and an opposing side. The at least one inorganic encapsulationlayer has a first side facing the flexible substrate and an opposingside. In the at least one bending area, at least one groove is formed onthe opposing side of the at least one organic encapsulation layer. Abottom width W of the at least one groove is configured to be

${W \geq {\frac{n}{180{^\circ}}\pi\; R}},$where n is a maximum bending angle of the at least one bending area,0°<n≤180°, and R is a bending radius of the at least one bending area.

Another aspect of the present disclosure provides a flexible displayapparatus comprising the disclosed flexible display panel.

Another aspect of the present disclosure provides a fabrication methodfor the flexible display panel. The fabrication method comprisesproviding a flexible substrate, forming an organic light-emitting layerhaving a first side facing the flexible substrate and an opposing sideon a side of the flexible substrate, and forming athin-film-encapsulation layer on the opposing side of the organiclight-emitting layer. The thin-film-encapsulation layer includes atleast one organic encapsulation layer and at least one inorganicencapsulation layer. The flexible display panel includes at least onebending area. At least one groove is formed on the opposing side of theat least one organic encapsulation layer in the at least one bendingarea. A bottom width W of the at least one groove is configured to be

${W \geq {\frac{n}{180{^\circ}}\pi\; R}},$where n is a maximum bending angle of the at least one bending area,0°<n≤180°, and R is a bending radius of the at least one bending area.

Other aspects of the present disclosure can be understood by thoseskilled in the art in light of the description, the claims, and thedrawings of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The following drawings are merely examples for illustrative purposesaccording to various disclosed embodiments and are not intended to limitthe scope of the present disclosure.

FIG. 1A illustrates a cross-sectional view of an existing display panel;

FIG. 1B illustrates a cross-sectional view of an exemplary flexibledisplay panel according to the disclosed embodiments;

FIG. 1C illustrates a cross-sectional view of an exemplary bent flexibledisplay panel according to the disclosed embodiments;

FIG. 1D illustrates a cross-sectional view of another exemplary bentflexible display panel according to the disclosed embodiments;

FIG. 2A illustrates a cross-sectional view of another exemplary flexibledisplay panel according to the disclosed embodiments;

FIG. 2B illustrates a cross-sectional view of another exemplary flexibledisplay panel according to the disclosed embodiments;

FIG. 2C illustrates a cross-sectional view of another exemplary flexibledisplay panel according to the disclosed embodiments;

FIG. 3A illustrates a cross-sectional view of another exemplary flexibledisplay panel according to the disclosed embodiments;

FIG. 3B illustrates a top view of another exemplary flexible displaypanel

FIG. 4A illustrates a cross-sectional view of another exemplary flexibledisplay panel according to the disclosed embodiments;

FIG. 4B illustrates a cross-sectional view of another exemplary flexibledisplay panel according to the disclosed embodiments;

FIG. 4C illustrates a top view of another exemplary flexible displaypanel according to the disclosed embodiments;

FIG. 4D illustrates a top view of another exemplary flexible displaypanel according to the disclosed embodiments;

FIG. 5 illustrates a schematic view of an exemplary display apparatusaccording to the disclosed embodiments;

FIG. 6A illustrates a flow chart of an exemplary flexible display panelfabrication method according to the disclosed embodiments;

FIG. 6B illustrates cross-sectional views of an exemplary flexibledisplay panel corresponding to each step of an exemplary fabricationmethod according to the disclosed embodiments;

FIG. 6C illustrates a flow chart of another exemplary flexible displaypanel fabrication method according to the disclosed embodiments; and

FIG. 6D illustrates a flow chart of another exemplary flexible displaypanel fabrication method according to the disclosed embodiments.

DETAILED DESCRIPTION

Reference will now be made in detail to exemplary embodiments of thedisclosure, which are illustrated in the accompanying drawings. Whereverpossible, the same reference numbers will be used throughout thedrawings to refer to the same or like parts. It should be understoodthat the exemplary embodiments described herein are only intended toillustrate and explain the present invention and not to limit thepresent invention. In addition, it should also be noted that, for easeof description, only part, but not all, of the structures associatedwith the present invention are shown in the accompanying drawings. Allother embodiments obtained by those skilled in the art without makingcreative work are within the scope of the present invention.

The present disclosure will now be described in detail with reference tothe accompanying drawings. When illustrating the embodiments of thepresent disclosure, certain areas of the schematic views of the devicestructures may be disproportionally enlarged for the convenience ofillustration. In addition, the three-dimensional sizes including thelength, width, and depth should be included in the actual implementationof the present disclosure.

FIG. 1A illustrates a cross-sectional view of an existing display panel.As shown in FIG. 1, the existing display panel often includes asubstrate 100, a thin-film-transistor layer 200 disposed on thesubstrate 100, an organic light-emitting layer 300 disposed on thethin-film-transistor layer 200, a thin-film-encapsulation layer 400disposed on the organic light-emitting layer 300, a polarization layer500 disposed on the thin-film-encapsulation layer 400, and a coveragewindow disposed on the polarization layer 500.

The thin-film-encapsulation layer 400 includes a first encapsulationsub-layer 420 and a second encapsulation sub-layer 440. The firstencapsulation sub-layer 420 is formed by an organic insulation material.The second encapsulation sub-layer 440 is formed by a resin material. Aportion of the second encapsulation sub-layer 440 in a bending area isremoved for reducing the bending stress. However, when bending theflexible display panel, the bending stress tends to concentrate in theareas 600 and, thus, the bending stress in the bending area may not beeffectively reduced. Further, the removal of the portion of the secondencapsulation sub-layer 440 in the bending area may significantlydegrade the encapsulation of the thin-film-encapsulation layer 400.

The present disclosure provides an improved flexible display panel. Theflexible display panel may comprise a flexible substrate, an organiclight-emitting layer disposed on a side of the flexible substrate andhaving a first side facing the flexible substrate and an opposing side,and a thin-film-encapsulation layer disposed on the opposing side of theorganic light-emitting layer. The thin-film-encapsulation layer mayinclude at least one organic encapsulation layer and at least oneinorganic encapsulation layer. The organic encapsulation layer may havea first side facing the organic light-emitting layer and an opposingside. The flexible display panel may include at least one bending area,where at least one groove may be formed on the opposing side of at leastone organic encapsulation layer. A width W at the bottom (i.e., thebottom width) of the groove may be configured to be

${W \geq {\frac{n}{180{^\circ}}\pi\; R}},$where n is a maximum bending angle of the bending area, 0°<n≤180°, and Ris a bending radius of the bending area.

FIG. 1B illustrates a cross-sectional view of an exemplary flexibledisplay panel according to the disclosed embodiments. As shown in FIG.1B, the flexible display panel may include a flexible substrate 11, anorganic light-emitting layer 12 disposed on a side of the flexiblesubstrate 11 and having a first side facing the flexible substrate andan opposing side, and a thin-film-encapsulation layer 13 disposed on theopposing side of the organic light-emitting layer 12. Thethin-film-encapsulation layer 13 may include an inorganic encapsulationlayer 131 and an organic encapsulation layer 132. The organicencapsulation layer 132 may have a first side facing the organiclight-emitting layer 12 and an opposing side.

The flexible display panel may include at least one bending area S. Theorganic encapsulation layer 132 in the bending area S may be formed withat least one groove 14 on the opposing side. The bottom width W of thegroove 14 may be configured to be

${W \geq {\frac{n}{180{^\circ}}\pi\; R}},$where n is a maximum bending angle of the bending area, 0°<n≤180°, and Ris a bending radius of the bending area.

In the disclosed embodiments, because at least one organic encapsulationlayer in the bending area S may be formed with at least one groove 14 onthe opposing side, the thickness of the flexible display panel at thebending area S may be reduced and, accordingly, the bending stressgenerated in the bending area S of the flexible display panel may bereduced. Moreover, when the bottom width W of the groove 14 isconfigured to be

${W \geq {\frac{n}{180{^\circ}}\pi\; R}},$the bending stress generated in the bending area S of the flexibledisplay panel may not concentrate at the groove 14, the intensity of thebending stress may be reduced, and certain portion of the bending stressin the groove 14 may be relieved.

In addition, the disclosed flexible display panel may reduce the bendingstress by reducing the thickness of certain sub-layers of thethin-film-encapsulation layer, instead of completely removing certainsub-layers of the thin-film-encapsulation layer in the existing flexibledisplay panel. Thus, the bending stress in the bending area may still beeffectively reduced and, meanwhile, ambient moisture and oxygen may beeffectively prevented from entering the organic light-emitting layerthrough the thin-film-encapsulation layer, thereby ensuring theencapsulation of the thin-film-encapsulation layer.

As shown in FIG. 1B, the thin-film-encapsulation layer 13 may includeone inorganic encapsulation layer 131 and one organic encapsulationlayer 132, which is for illustrative purposes and is not intended tolimit the scope of the present disclosure. In another embodiment, thenumber of the inorganic encapsulation layers and the number of theorganic encapsulation layers each may be configured to be greater than1.

Referring to FIG. 1B, the organic light-emitting layer 12 may include aplurality of organic light-emitting devices arranged in array. Theorganic light-emitting device may include any appropriate organiclight-emitting devices. In one embodiment, the organic light-emittingdevice may include a first electrode, an organic light-emitting layer,and a second electrode, which are stacked sequentially. Athin-film-transistor layer may be disposed between the organiclight-emitting layer 12 and the flexible substrate 11. Thethin-film-transistor layer may include a plurality ofthin-film-transistors, storage capacitors, data lines, gate lines, powersupply voltage lines, and ground lines, etc.

The thin-film-encapsulation layer 13 may be configured to encapsulatethe organic light-emitting device and the thin-film-transistors. Thethin-film-encapsulation layer 13 may prevent ambient moisture and oxygenfrom entering the organic light-emitting devices, thereby protecting theorganic light-emitting devices. The thin-film-encapsulation layer 13 mayalso protect the thin-film-transistors.

In one embodiment, the organic encapsulation layer 132 may be made ofany one of acrylic, epoxy, and silicone material. The organicencapsulation layer 132 may be formed by an ink jet printing process.The ink jet printing is simple and reliable, through which the organicencapsulation layer 132 may be formed without masks. The inorganicencapsulation layer 131 may be formed by a chemical vapor deposition(CVD) or atomic layer deposition (ALD) process.

FIG. 1C illustrates a cross-sectional view of an exemplary bent flexibledisplay panel according to the disclosed embodiments. As shown in FIG.1C, the flexible display panel may include three areas, a first area A1,a bending area S, and a second area A2. The bending area S may belocated between the first area A1 and the second area A2, and may beadjacent to and in contact with the first area A1 and the second areaA2. That is, the first area A1 and the second area A2 may be extensionareas on both sides of the bending area S.

A bending angle of the bending area S may be defined as a bending angleα of the second area A2 with respect to the first area A1. The bendingradius R may be defined as a shortest distance between a center of thecircle formed by the bending area S and the bottom of the groove 14. Thebending R radius may be greater than or equal to about 0.1 mm. When thebending radius R is smaller than 0.1 mm, the flexible display panel maynot be bent easily. Excessive bending stress may occur in the bendingarea S, thereby increasing the risk of the flexible display panelbreakage. When the bending radius R is greater than or equal to 0.1 mm,the bending stress in the bending area S may be substantially small,thereby reducing the risk of the flexible display panel breakage.

FIG. 1D illustrates a cross-sectional view of another exemplary bentflexible display panel according to the disclosed embodiments. As shownin FIG. 1D, the flexible display panel may be bent to a position havinga bending angle of about 180° of the bending area S. Because the groove14 is formed on the organic encapsulation layer 132 and is correspondingto the bending area S, the thickness of the flexible display panel inthe bending area S may be reduced, and the bending stress in the bendingarea S of the flexible display panel may be reduced.

In addition, because the bottom width W of the groove 14 is configuredto be

${W \geq {\frac{n}{180{^\circ}}\pi\; R}},$i.e., W≥πR and a first climbing position 201 and a second climbingposition 202 may be located just outside the bending area S, the bendingstress in the bending area S may not concentrate at the first climbingposition 201 and the second climbing position of the groove 14. Thus,the organic encapsulation layer 132 may be prevented from cracking orbreaking at the first climbing position 201 and the second climbingposition 202.

The organic encapsulation layer 132 may be disposed in the bending areaS. The organic encapsulation layer 132 and the inorganic encapsulationlayer 131 disposed in the bending area S may be coordinated toeffectively block ambient moisture and oxygen, thereby reducing thebending stress in the bending area S and, meanwhile, ensuring theeffective encapsulation of the thin-film-encapsulation layer 13 in thebending area S.

Further, in one embodiment, the width of the bottom of the groove 14 maybe configured to W=πR. Because the groove 14 is formed in the bendingarea S, when the bottom width of the groove 14 is configured to be W=πR,the bottom width of the groove 14 may be equal to a width of the bendingarea S, thereby reducing the bending stress in the bending area S and,meanwhile, ensuring the effective encapsulation of thethin-film-encapsulation layer 13.

Returning to FIG. 1B, in one embodiment, the organic encapsulation layer132 formed with the groove 14 may have a thickness d2 of approximatelybetween 2 μm and 40 μm, and the groove 14 may have a thickness d1 ofapproximately between 1 μm and 20 μm. The organic encapsulation layer132 may relieve the bending stress generated between the inorganicencapsulation layers 131 and increase invasion paths of moisture andoxygen. However, when the organic encapsulation layer 132 issubstantially thick, the neutral plane may be deviated from the organiclight-emitting layer 12, damaging the organic light-emitting layer 12when bending the flexible display panel, and degrading displayperformance. In addition, when the organic encapsulation layer 132 issubstantially thick, the bending radius may increase. Thus, the organicencapsulation layer 132 formed with the groove 14 may be configured tohave the thickness d2 of approximately between 2 μm and 40 μm, and thegroove 14 may be configured to have the thickness d1 of approximatelybetween 1 μm and 20 μm.

FIG. 2A illustrates a cross-sectional view of another exemplary flexibledisplay panel according to the disclosed embodiments. The similaritiesbetween FIG. 2A and FIG. 1B are not repeated here, while certaindifferences will be explained.

As shown in FIG. 2A, the organic encapsulation layer 132 may furtherinclude a first organic encapsulation sub-layer 1321 and a secondorganic encapsulation sub-layer 1322. The first organic encapsulationsub-layer 1321 may be continuously disposed to cover the entire flexibledisplay panel. The second organic encapsulation sub-layer 1322 may bediscontinued in the bending area S, thereby forming at least one groove14.

FIG. 2B illustrates a cross-sectional view of another exemplary flexibledisplay panel according to the disclosed embodiments. In anotherembodiment, as shown in FIG. 2B, the flexible display panel may includea flexible substrate 11, an organic light-emitting layer 12 disposed ona side of the flexible substrate 11 and having a first side facing theflexible substrate and an opposing side, a thin-film-encapsulation layer13 disposed on the opposing side of the organic light-emitting layer 12.The thin-film-encapsulation layer 13 may include a first inorganicencapsulation layer 131, a second inorganic encapsulation layer 133, anda first organic encapsulation layer 132 disposed between the firstinorganic encapsulation layer 131 and the second inorganic encapsulationlayer 133. The first inorganic encapsulation layer 131 may be disposedbetween the organic light-emitting layer 12 and the first organicencapsulation layer 132. The first organic encapsulation layer 132 maybe formed with at least one groove 14 in the bending area S.

The first inorganic encapsulation layer 131 and the second inorganicencapsulation layer 133 may easily have cracks when being bent, due tothe material properties of inorganic encapsulation layers. Throughconfiguring the first organic encapsulation layer 132 to have at leastone groove 14 formed in the bending area S, the bending stress may bereduced. Accordingly, the second inorganic encapsulation layer 133disposed on the first organic encapsulation layer 132 may be preventedfrom cracking or breaking caused by excessive bending stress when beingbent, and the encapsulation effectiveness of the thin-film-encapsulationlayer 13 may be ensured.

FIG. 2C illustrates a cross-sectional view of another exemplary flexibledisplay panel according to the disclosed embodiments. The similaritiesbetween FIG. 2C and FIG. 1B are not repeated here, while certaindifferences will be explained.

As shown in FIG. 2C, the flexible display panel may include a flexiblesubstrate 11, an organic light-emitting layer 12 disposed on a side ofthe flexible substrate 11 and having a first side facing the flexiblesubstrate and an opposing side, a thin-film-encapsulation layer 13disposed on the opposing side of the organic light-emitting layer 12.The thin-film-encapsulation layer 13 may include a first inorganicencapsulation layer 131, a first organic encapsulation layer 132, asecond inorganic encapsulation layer 133, a second organic encapsulationlayer 134, and a third inorganic encapsulation layer 135.

Either the first organic encapsulation layer 132 or the second organicencapsulation layer 134 may be configured with at least one groove 14 inthe bending area S, such that the bending stress may be reduced, and atleast one of the second inorganic encapsulation layer 133 disposed onthe first organic encapsulation layer 132 and the third inorganicencapsulation layer 135 disposed on the second organic encapsulationlayer 134 may be prevented from cracking or breaking caused by anexcessive bending stress when being bent. Employing three inorganicencapsulation layers and two organic encapsulation layers may ensure theencapsulation effectiveness of the thin-film-encapsulation layer 13, andmay improve the life span of the flexible display panel.

FIG. 3A illustrates a cross-sectional view of another exemplary flexibledisplay panel according to the disclosed embodiments. The similaritiesbetween FIG. 3A and FIG. 1B are not repeated here, while certaindifferences will be explained.

As shown in FIG. 3A, the flexible display panel may further include atleast one of a first curved line 151 and a second curved line 152. Thefirst curved line 151 may be disposed transitioning between the bottomof the groove 14 and the side wall of the groove 14, and the secondcurved line 152 may be disposed transitioning between the side wall ofthe groove 14 and the non-recessed surface of the organic encapsulationlayer 132.

The transition between the bottom of the groove 14 and the side wall ofthe groove 14 may be smoothed through the first curved line 151. Whenbeing bent, the bending stress at the bottom and on the side wall of thegroove 14 may be further reduced. Thus, the risk of cracks in theorganic encapsulation layer 132 may be further reduced, and the bendingperformance of the flexible display panel when being bent may beimproved.

An angle α formed between the first curved line 151 and the bottom ofthe groove 14 may be determined according to various applicationscenarios. In one embodiment, the angle α formed between the firstcurved line 151 and the bottom of the groove 14 may be greater thanabout 0° and smaller than or equal to about 70°, i.e., 0°<α≤70°. Inanother embodiment, the angle α formed between the first curved line 151and the bottom of the groove 14 may be greater than about 15° andsmaller than or equal to about 70°, i.e., 15°<α≤70°. When the angle αformed between the first curved line 151 and the bottom of the groove 14is large, for example, greater than about 70° and smaller than or equalto about 90°, a substantially large bending stress may be generated whenthe flexible display panel is bent. The bending stress may likelyconcentrate in the groove 14, thereby causing the groove 14 to crack orbreak.

When the angle α formed between the first curved line 151 and the bottomof the groove 14 is sustainably small, the bottom width of the groove 14may be sustainably wide, and the groove 14 may extend into the displayarea of the flexible display panel, thereby causing the light emittedfrom the display area to refract and reflect, and degrading the displayperformance of the flexible display panel. Thus, the angle α formedbetween the first curved line 151 and the bottom of the groove 14 may beconfigured to be greater than about 15° and smaller than or equal toabout 70°, i.e., 15°<α≤70°.

Similarly, an angle β formed between the second curved line 152 and thenon-recessed surface of the organic encapsulation layer 132 may bedetermined according to various application scenarios. In oneembodiment, the angle β formed between the second curved line 152 andthe non-recessed surface of the organic encapsulation layer 132 may begreater than about 0° and smaller than or equal to about 60°, i.e.,0°<β≤60°. In another embodiment, the angle β formed between the secondcurved line 152 and the non-recessed surface of the organicencapsulation layer 132 may be greater than about 15° and smaller thanor equal to about 70°, i.e., 15°<β≤70°. When the angle β formed betweenthe second curved line 152 and the non-recessed surface of the organicencapsulation layer 132 is large, for example, greater than about 70°and smaller than or equal to about 90°, a substantially large bendingstress may be generated when the flexible display panel is bent. Thebending stress may likely concentrate in the groove 14, thereby causingthe groove 14 to crack or break.

When the angle β formed between the second curved line 152 and thenon-recessed surface of the organic encapsulation layer 132 issubstantially small, the bottom width of the groove 14 may be wide, andthe groove 14 may extend into the display area of the flexible displaypanel, thereby causing the light emitted from the display area torefract and reflect, and degrading the display performance of theflexible display panel. Thus, the angle β formed between the secondcurved line 152 and the non-recessed surface of the organicencapsulation layer 132 may be configured to be greater than about 15°and smaller than or equal to about 45°, i.e., 15°<β≤45°.

In the disclosed embodiments, one bending area may include a pluralityof grooves. That is, a plurality of grooves may be disposed in the samebending area. When the plurality of the grooves is configured in thesame bending area, the plurality of the grooves may be arranged inparallel in a direction perpendicular to an extension direction of thegroove. An exemplary structure is shown in FIG. 3B.

FIG. 3B illustrates a top view of another exemplary flexible displaypanel according to the disclosed embodiments. As shown in FIG. 3B, onebending area of the flexible display panel may include two grooves 14.The grooves 14 may extend in a direction Y. The two grooves 14 may bearranged in parallel in a direction X. The direction X may beperpendicular to the extension direction Y of grooves 14. The number ofthe grooves 14, the directions X and Y in FIG. 3B are for illustrativepurposes and are not intended to limit the scope of the presentdisclosure.

The flexible display panel may include a display area and a non-displayarea surrounding the display area. At least one of the display area andthe non-display area may be configured with at least one bending area.The display area may be an area for image display, and the non-displayarea may be an area not for image display.

Further, the non-display area of the flexible display panel may bedisposed with a peripheral circuit. An orthogonal projection of theperipheral circuit onto the flexible substrate may partially overlapwith an orthogonal projection of the bending area onto the flexiblesubstrate. An exemplary structure is shown in FIG. 4A.

FIG. 4A illustrates a cross-sectional view of another exemplary flexibledisplay panel according to the disclosed embodiments. As shown in FIG.4A, the flexible display panel may include a display area B1 and anon-display area B2. The non-display area B2 of the flexible displaypanel may be configured with a peripheral circuit 16. An orthogonalprojection of the peripheral circuit 16 onto the flexible substrate 11may partially overlap with an orthogonal projection of the bending areaS onto the flexible substrate 11. Thus, the bending area S may notseparately occupy the non-display area B2 of the flexible display panel,thereby facilitating a narrow frame design of the flexible displaypanel.

The peripheral circuit may include thin-film-transistors and metalwirings. That is, the bending area S may bend downwards from the edge ofthe display area B1, and may be located in the non-display area B2. Invarious practical applications, after the bending area S is bent, thenon-display area 132 may become a side wall of the flexible displaypanel. When the flexible display panel is incorporated in a displayapparatus, the bending area S may be bent, such that the non-displayarea B2 may become a side wall of the display apparatus, or thenon-display area B2 may be folded to the back wall of the display areaB1. Thus, a borderless design of the display apparatus may be achieved,and non-display area B2 may be called an edge area or border area.

FIG. 4B illustrates a cross-sectional view of another exemplary flexibledisplay panel according to the disclosed embodiments. In one embodiment,as shown in FIG. 4B, the flexible display panel may include a flexiblesubstrate 11, an organic light-emitting layer 12 disposed on a side ofthe flexible substrate 11 and having a first side facing the flexiblesubstrate and an opposing side, and a thin-film-encapsulation layer 13disposed on the opposing side of the organic light-emitting layer 12.The thin-film-encapsulation layer 13 may include a first inorganicencapsulation layer 131, a second inorganic encapsulation layer 133, anda first organic encapsulation layer 132. The first organic encapsulationlayer 132 may be disposed between the first inorganic encapsulationlayer 131 and the second inorganic encapsulation layer 133. The firstinorganic encapsulation layer 131 may be disposed between the organiclight-emitting layer 12 and the first organic encapsulation layer 132.The first organic encapsulation layer 132 may be configured with atleast one groove 14 in the bending area S.

The flexible display panel may also include a display area. The displayarea may include a first display area A1 and a second display area A2.Both the first display area A1 and the second display area A2 may belocated adjacent to the bending area S. The bending area S may bedisposed between the first display area A1 and the second display areaA2. That is, the bending area S may also be located in the display area.However, the bending area S may be located in a non-light-emitting areaof the display area.

In particular, an orthogonal projection of the groove 14 on the organiclight-emitting layer 12 may be located between two adjacent rows or twoadjacent columns of sub-pixels. That is, in a direction perpendicular tothe flexible display panel, the thin-film-encapsulation layer 13 in thearea of sub-pixels may not be configured with any groove 14. Thus, thearea of sub-pixels in the thin-film-encapsulation layer 13 may besubstantially flat, such that the optical properties of the sub-pixelsby the groove 14 may not be degraded by the groove 14.

In another embodiment, as shown in FIG. 4B, the flexible display panelmay include a flexible substrate 11, an organic light-emitting layer 12disposed on a side of the flexible substrate 11 having a first sidefacing the flexible substrate and an opposing side, and athin-film-encapsulation layer 13 disposed on the opposing side of theorganic light-emitting layer 12. The thin-film-encapsulation layer 13may include a first inorganic encapsulation layer 131, a secondinorganic encapsulation layer 133, and a first organic encapsulationlayer 132. The first organic encapsulation layer 132 may be disposedbetween the first inorganic encapsulation layer 131 and the secondinorganic encapsulation layer 133. The first inorganic encapsulationlayer 131 may be disposed between the organic light-emitting layer 12and the first organic encapsulation layer 132. The first organicencapsulation layer 132 may be configured with at least one groove 14 inthe bending area S.

The flexible display panel may also include a first display area A1 anda second display area A2. The first display area A1 and the seconddisplay area A2 may display different images. The bending area S may bedisposed between the first display area A1 and the second display areaA2. That is, the bending area S may bend downwards from an edge of thefirst display area A1. The bending area S may be a non-display area. Thesecond display area A2 may be an area extended outward from the bendingarea S. In various practical applications, when the flexible displaypanel is incorporated in a display apparatus, the flexible display panelmay display different images in the first display area A1 and the seconddisplay area A2. Thus, the display apparatus may be a double-sideddisplay apparatus.

FIG. 4C illustrates a top view of another exemplary flexible displaypanel according to the disclosed embodiments. As shown in FIG. 4C, aplurality of grooves 14 may be disposed between two adjacent columns ofpixels 17. The groove 14 may be arranged in a straight line in anextension direction of the groove 14. That is, the groove 14 may have astraight line shape.

FIG. 4D illustrates a top view of another exemplary flexible displaypanel according to the disclosed embodiments. As shown in FIG. 4D, aplurality of grooves 14 may be disposed between any two adjacent columnsof pixels 17. The groove 14 may be arranged in a folded line in anextension direction of the groove 14. That is, the groove 14 may have afolded line shape.

The arrangement and the shape of the grooves 14 in FIG. 4C and FIG. 4Dare for illustrative purposes and are not intended to limit the scope ofthe present disclosure.

In practical applications, the grooves 14 may be arranged in a wayadapting to the shape and arrangement of the pixels.

The present disclosure also provides a display apparatus. The displayapparatus may include a disclosed flexible display panel. FIG. 5illustrates a schematic view of an exemplary display apparatus accordingto the disclosed embodiments. As shown in FIG. 5, the display apparatus51 may include a flexible display panel 52. The flexible display panel52 may be any one of the disclosed flexible display panels. Although asmart phone is shown in FIG. 16, the touch control display apparatus 1may be a smart watch, a VR goggle, a smart hand band, an electronicpaper, a television set, an automotive display, a notebook computer, atablet computer, or any appropriate touch control display apparatus,which is not limited by the present disclosure.

FIG. 6A illustrates a flow chart of an exemplary fabrication method foran exemplary flexible display panel according to the disclosedembodiments. FIG. 6B illustrates cross-sectional views of an exemplaryflexible display panel corresponding to each step of an exemplaryfabrication method according to the disclosed embodiments. As shown inFIG. 6A, at the beginning, a flexible substrate is provided (S610).After the flexible substrate is provided, an organic light-emittinglayer is formed on the flexible substrate (S620). The correspondingstructure is shown in FIG. 6B.

As shown in FIG. 6B, the organic light-emitting layer 12 may be formedby sputtering, vapor deposition, or similarly appropriate processes. Inparticular, through sputtering or vapor deposition, a first electrode ofan organic light-emitting device may be formed in the organiclight-emitting layer 12 on the flexible substrate 11. The firstelectrode may have a first side facing the flexible substrate and anopposing side. After the first electrode is formed, through sputteringor vapor deposition, an organic light-emitting material layer may beformed on the opposing side of the first electrode. The organiclight-emitting material layer may have a first side facing the flexiblesubstrate and an opposing side. After the organic light-emittingmaterial layer is formed, through sputtering or vapor deposition, asecond electrode may be formed on the opposing side of the organiclight-emitting material layer. The first electrode or the secondelectrode may be a transparent electrode, a semi-transparent electrode,or a reflective electrode.

Returning to FIG. 6A, after the organic light-emitting layer is formedon the flexible substrate, the organic light-emitting layer has a firstside facing the flexible substrate and an opposing side, athin-film-encapsulation layer is formed on the opposing side of theorganic light-emitting of the flexible substrate (S630). Thecorresponding structure is shown in FIG. 6B.

As shown in FIG. 6B, the organic light-emitting layer 12 may have afirst side facing the flexible substrate 11 and an opposing side. Thethin-film-encapsulation layer 13 may be formed on the opposing side ofthe organic light-emitting layer 12. The thin-film-encapsulation layer13 may include at least one organic encapsulation layer 132 and at leastone inorganic encapsulation layer 131. The organic encapsulation layer132 may have a first side facing the flexible substrate 11 and anopposing side. The inorganic encapsulation layer 131 may have a firstside facing the flexible substrate 11 and an opposing side. Thefabricated flexible display panel may include at least one bending area.At least one groove may be formed on the opposing side of at least oneorganic encapsulation layer 132 in the bending area.

A bottom width W of the groove may be configured to be

${W \geq {\frac{n}{180{^\circ}}\pi\; R}},$where n is a maximum bending angle of the bending area, 0°<n≤180°, and Ris a bending radius of the bending area. In one embodiment, the bottomwidth W of the groove may be configured to be W=πR.

In the disclosed embodiments, the organic encapsulation layer 132 mayformed by an ink jet printing process. The organic encapsulation layer132 may be formed together with the groove by the same ink jet printingprocess. The inorganic encapsulation layer 131 may be formed by achemical vapor deposition (CVD) process or an atomic layer deposition(ALD) process.

FIG. 6C illustrates a flow chart of another exemplary fabrication methodfor an exemplary flexible display panel according to the disclosedembodiments. The corresponding structure is shown in FIG. 6B. Thesimilarities between FIG. 6C and FIG. 6A are not repeated here, whilecertain differences will be explained.

As shown in FIG. 6C, at the beginning, a flexible substrate is provided(S611). After the flexible substrate is provided, an organiclight-emitting layer is formed on a side of the flexible substrate(S612). After the organic light-emitting layer is formed on the flexiblesubstrate, an inorganic encapsulation layer is formed on the opposingside of the organic light-emitting layer (S613). After the inorganicencapsulation layer is formed on the organic light-emitting layer,through ink jet printing, a first organic encapsulation sub-layer isformed continuously on the opposing side of the inorganic encapsulationlayer, and then a second organic encapsulation sub-layer is formed onthe opposing side of the first organic encapsulation layer, and at leastone groove is formed by discontinuing the second organic encapsulationsub-layer in the bending area (S614).

The inorganic encapsulation layer may be disposed between the organiclight-emitting layer and the first organic encapsulation sub-layer.

FIG. 6D illustrates a flow chart of another exemplary fabrication methodfor an exemplary flexible display panel according to the disclosedembodiments. The corresponding structure is shown in FIG. 6B. Thesimilarities between FIG. 6D and FIG. 6A are not repeated here, whilecertain differences will be explained.

As shown in FIG. 6D, at the beginning, a flexible substrate is provided(S621). After the flexible substrate is provided, an organiclight-emitting layer is firmed on a side of the flexible substrate(S622). After the organic light-emitting layer is formed on the flexiblesubstrate, an inorganic encapsulation layer is formed on opposing sideof the organic light-emitting layer (S623). After the inorganicencapsulation layer is formed on the organic light-emitting layer,through ink jet printing, an organic encapsulation layer is formed onthe opposing side of the inorganic encapsulation layer, and at least onegroove is formed by discontinuing the organic encapsulation layer in thebending area (S624).

The inorganic encapsulation layer may be disposed between the organiclight-emitting layer and the organic encapsulation layer. Through inkjet printing, the organic encapsulation layer and at least one groovemay be formed at the same time.

The present disclosure provides an improved flexible display panel. Theflexible display panel may comprise a flexible substrate, an organiclight-emitting layer disposed on a side of the flexible substrate andhaving a first side facing the flexible substrate and an opposing side,and a thin-film-encapsulation layer disposed on the opposing side of theorganic light-emitting layer. The thin-film-encapsulation layer mayinclude at least one organic encapsulation layer and at least oneinorganic encapsulation layer. The organic encapsulation layer may havea first side facing the organic light-emitting layer and an opposingside. The flexible display panel may include at least one bending area,where at least one groove may be formed on the opposing side of at leastone organic encapsulation layer. A width W at the bottom (i.e., thebottom width) of the groove may be configured to be

${W \geq {\frac{n}{180{^\circ}}\pi\; R}},$where n is a maximum bending angle of the bending area, 0°<n≤180°, and Ris a bending radius of the bending area.

It should be noted that the various embodiments in the presentspecification are described in a progressive manner. Each embodiment ismainly described in terms of differences from the previously describedembodiments. The similarities between different embodiments are notrepeated, and may be incorporated by references.

Various embodiments have been described to illustrate the operationprinciples and exemplary implementations. It should be understood bythose skilled in the art that the present invention is not limited tothe specific embodiments described herein and that various other obviouschanges, rearrangements, and substitutions will occur to those skilledin the art without departing from the scope of the invention. Thus,while the present invention has been described in detail with referenceto the above described embodiments, the present invention is not limitedto the above described embodiments, but may be embodied in otherequivalent forms without departing from the scope of the presentinvention, which is determined by the appended claims.

What is claimed is:
 1. A flexible display panel, comprising: a flexiblesubstrate; an organic light-emitting layer disposed on a side of theflexible substrate and having a first side facing the flexible substrateand an opposing side; and a thin-film-encapsulation layer disposed onthe opposing side of the organic light-emitting layer and including atleast one organic encapsulation layer and at least one inorganicencapsulation layer, wherein: the flexible display panel includes atleast one bending area; the at least one organic encapsulation layer hasa first side facing the flexible substrate and an opposing side; the atleast one inorganic encapsulation layer has a first side facing theflexible substrate and an opposing side; in the at least one bendingarea, at least one groove is formed on the opposing side of the at leastone organic encapsulation layer; and a bottom width W of the at leastone groove is configured to be${W \geq {\frac{n}{180{^\circ}}\pi\; R}},$ where n is a maximum bendingangle of the at least one bending area, 0°<n≤180°, and R is a bendingradius of the at least one bending area.
 2. The flexible display panelaccording to claim 1, wherein: the bottom width W of the at least onegroove is configured to be W=πR.
 3. The flexible display panel accordingto claim 1, wherein: the bending radius R is greater than or equal toabout 0.1 mm.
 4. The flexible display panel according to claim 1,wherein: the at least one organic encapsulation layer includes a firstorganic encapsulation sub-layer and a second organic encapsulationsub-layer; the first organic encapsulation sub-layer is configuredcontinuously; the second organic encapsulation sub-layer is discontinuedin the at least one bending area to form the at least one groove; andthe second organic encapsulation sub-layer is configured on the opposingside of the first organic encapsulation sub-layer.
 5. The flexibledisplay panel according to claim 1, wherein: the at least one organicencapsulation layer is formed by an ink jet printing process.
 6. Theflexible display panel according to claim 1, wherein: thethin-film-encapsulation layer includes a first inorganic encapsulationlayer, a second inorganic encapsulation layer, and a first organicencapsulation layer, wherein the first organic encapsulation layer isdisposed between the first inorganic encapsulation layer and the secondinorganic encapsulation layer; the first inorganic encapsulation layeris disposed between the organic light-emitting layer and the firstorganic encapsulation layer; and in the at least one bending area, theat least one groove is formed on the first organic encapsulation layer.7. The flexible display panel according to claim 1, wherein: thethin-film-encapsulation layer includes a first inorganic encapsulationlayer, a first organic encapsulation layer, a second inorganicencapsulation layer, a second organic encapsulation layer, and a thirdinorganic encapsulation layer, which are configured sequentially on theopposing side of the organic light-emitting layer, and in the at leastone bending area, the at least one groove is formed in either the firstorganic encapsulation layer or the second organic encapsulation layer.8. The flexible display panel according to claim 1, wherein: the atleast one organic encapsulation layer is configured with the at leastone groove and has a thickness of approximately between 2 μm and 40 μm;and the at least one groove has a thickness of approximately between 1μm and 20 μm.
 9. The flexible display panel according to claim 1,comprising at least one of the following: a bottom of the at least onegroove transitions to a side wall of the at least one groove through afirst curved line; and the side wall of the at least one groovetransitions to a non-recessed surface of the at least one organicencapsulation layer through a second curved line.
 10. The flexibledisplay panel according to claim 9, wherein: an angle α between thefirst curved line and the bottom of the at least one groove isapproximately in a range of 0°<α≤70°.
 11. The flexible display panelaccording to claim 10, wherein: an angle β between the second curvedline and the non-recessed surface of the at least one organicencapsulation layer is approximately in a range of 0°<β≤60°.
 12. Theflexible display panel according to claim 9, wherein: an angle α betweenthe first curved line and the bottom of the at least one groove isapproximately in a range of 15°<α≤70°.
 13. The flexible display panelaccording to claim 12, wherein: an angle β between the second curvedline and the non-recessed surface of the at least one organicencapsulation layer is approximately in a range of 15°<β≤45°.
 14. Theflexible display panel according to claim 1, wherein: the at least onebending area includes a plurality of grooves; and the plurality of thegrooves is arranged in parallel in a direction perpendicular to anextension direction of a groove.
 15. The flexible display panelaccording to claim 1, wherein: the at least one organic encapsulationlayer is made of acrylic, epoxy, or silicone materials.
 16. The flexibledisplay panel according to claim 1, wherein: the flexible display panelincludes a display area and a non-display area surrounding the displayarea; and at least one of the display area and the non-display area isconfigured with the at least one bending area.
 17. The flexible displaypanel according to claim 16, wherein: a peripheral circuit is configuredin the non-display area; and the peripheral circuit at least partiallyoverlaps with the at least one bending area in a direction perpendicularto the flexible substrate.
 18. The flexible display panel according toclaim 16, wherein: the display area includes two sections; and the atleast one bending area is disposed between the two sections of thedisplay area.
 19. The flexible display panel according to claim 18,wherein: the display area includes two sections for displaying differentimages; and the at least one bending area is disposed between the twosections of the display area.
 20. The flexible display panel accordingto claim 16, wherein: an orthogonal projection of the at least onegroove onto the organic light-emitting layer is located between two rowsor two columns of sub-pixels.
 21. The flexible display panel accordingto claim 16, wherein: the flexible display panel includes a plurality ofbending areas; and a plurality of grooves in the plurality of thebending areas are arranged in parallel.
 22. The flexible display panelaccording to claim 16, wherein: the at least one groove is arranged in astraight line or a folded line in an extension direction of the at leastone groove.
 23. A flexible display apparatus, comprising the flexibledisplay panel according to claim
 1. 24. A fabrication method for theflexible display panel, comprising: providing a flexible substrate;forming an organic light-emitting layer having a first side facing theflexible substrate and an opposing side on a side of the flexiblesubstrate; and forming a thin-film-encapsulation layer on the opposingside of the organic light-emitting layer, wherein: thethin-film-encapsulation layer includes at least one organicencapsulation layer and at least one inorganic encapsulation layer; theflexible display panel includes at least one bending area; at least onegroove is formed on the opposing side of the at least one organicencapsulation layer in the at least one bending area; and a bottom widthW of the at least one groove is configured to be${W \geq {\frac{n}{180{^\circ}}\pi\; R}},$ where n is a maximum bendingangle of the at least one bending area, 0°<n≤180°, and R is a bendingradius of the at least one bending area.
 25. The fabrication methodaccording to claim 24, wherein: the bottom width W of the at least onegroove is configured to be W=πR.
 26. The fabrication method according toclaim 24, wherein: the at least one organic encapsulation layer isformed by an ink jet printing process.
 27. The fabrication methodaccording to claim 26, wherein forming the at least one organicencapsulation layer includes: through an ink jet printing process,forming a continuous first organic encapsulation sub-layer having afirst side facing the flexible substrate and an opposing side; throughthe ink jet printing process, forming a second organic encapsulationsub-layer on the opposing side of the first organic encapsulationsub-layer; and forming the at least one groove by discontinuing thesecond organic encapsulation sub-layer in the at least one bending area.28. The fabrication method according to claim 24, wherein forming the atleast one organic encapsulation layer includes: through an ink jetprinting process, forming the at least one organic encapsulation layer,discontinuing the at least one organic encapsulation layer in the atleast one bending area to form the at least one groove.